Guide wire and production method therefor

ABSTRACT

A guide wire comprising an inner core (a) having, integrally formed together, a body portion (a-1) high in rigidity and a tip end portion (a-2) smaller in diameter and lower in rigidity than the (a-1), an a high X-ray contrast unit (b) provided at the (a-2), the (a-2) being resin-molded with the (b) contained therein, wherein the guide wire having the high X-ray contrast unit (coil) integrally formed with resin allows no blood to enter the coil, no thrombus to be formed, and the coil not to shrink or expand or come off when the guide wire is to be removed, and an elastomer used for metal powder-contained rubber portion at the front tip end is soft and not likely to damage blood vessels, whereby it is possible to materialize a very fine guide wire having an inner core with an outer diameter of 0.25-0.31 mm.

TECHNICAL FIELD

The invention relates to an innovative guide wire and its productionmethod. More particularly, the invention relates to a guide wirecomprising a high x-ray contrast unit and an inner core integrated byresin molding and its production method.

BACKGROUND OF THE INVENTION

For inspection and treatment of a human body, a catheter is commonlyinserted into the tissues and the coeloms of a human body such as theblood vessel, the trachea, the urethra and the like. At the time ofleading the catheter to an aimed point of the body, a guide wire is usedfor guiding the catheter to the aimed point while being inserted intothe catheter and its tip end being slightly projected out of the tip ofthe catheter. Further, recently, it has been tried to introduce thecatheter into a thinner blood vessel such as inner blood vessels of thebrain or blood vessels composing the kidney and thus the catheter isneed to be further thinner and accordingly, the guide wire is alsorequired to be thin (Japanese Patent Application Laid-Open No.2-180277).

However, it has been difficult to make an ultra-thin guide wirepractically available since there have been various problems andobstacles. For example, a guide wire for the brain comprises the mainpart of the tapered part covered with a coil (a high x-ray contrastunit) and therefore no main tip end portion with a lubricating propertycan be obtained. Further, since there is a space between the core wireand the coil in the main part, blood enters in the space to be athrombus or if the guide wire once has a habit of curving, it cannot beamended. For example, once a doctor fails to make the shape of a guidewire as he likes, it cannot be amended. No extremely thin guide wirewith an outer diameter of 0.25 to 0.31 mm and sufficient for practicaluse exists. Further, a metal such as a silver solder is used for themost tip end portion, so that the blood vessel is sometimes damaged.

Based on the investigations carried out for solving such problems,inventors have developed a guide wire having a specified structure and aguide wire coated with a lubricating coating by a specified productionmethod using a specified material to solve the above-mentioned problemsand accordingly have accomplished the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing in the left of FIG. 1 is a perspective view showing a guidewire of the invention at the time of production and the drawing in theright is its vertical cross-sectional view.

FIG. 2 is a vertical cross-sectional view of a guide wire completed.

FIG. 3 is a cross-sectional view showing the method of an underwaterlubrication test.

FIG. 4 is a graph showing the result of the underwater lubrication test.

DESCRIPTION OF THE SYMBOLS

-   1 an inner core-   2 a tip end portions-   3 high x-ray contrast unit (coil-like) 4 a tube made of resin 5 a    tube made of a metal 6 a seal member-   7 a plug-   8 a main body parts-   9 the most tip end portion (corresponding to semicircular rubber)-   10 x-ray contrast unit comprising integrally formed resin and coil-   11 a coil and resin-   12 a lubricating coating 13 a cylindrical container 14 a cylinder 15    a silicone sheet-   16 an opening parts 17 a sample

DISCLOSURE OF THE INVENTION

A purpose of the invention is to provide a guide wire with high safetywhich comprises a high x-ray contrast unit (a coil) and resin integratedtogether so as to prevent blood from entering in the coil and forming athrombus and of which the coil is prevented from expansion andcontraction or from coming off when the guide wire is taken out.

Another purpose of the invention is to make a guide wire comprising aninner core with an outer diameter of 0.25 to 0.31 mm practicallyavailable.

Further another purpose of the invention is to provide a guide wirewhich has a lubricating coating with durability in an optional length,uses an elastomer for the most tip end portion of a metal powder-mixedrubber, is soft and hardly damages the blood vessel.

That is, the invention is as described in the following guide wires of(1) to (IV):

-   (I) a guide wire comprising an inner core (a) composed of a main    body portion (a-1) with a high rigidity and a tip end portion (a-2)    smaller in diameter and lower in rigidity than the main body portion    (a-1) and integrally formed together with the main body portion    (a-1) and a high x-ray contrast unit (b) formed at the tip end    portion (a-2), wherein the tip end portion (a-2) is resin-molded    with the (b) contained therein;-   (II) the guide wire wherein the tip end of the tip end portion (a-2)    is made of a metal powder-mixed rubber;-   (III) the guide wire wherein the surface is entirely or partially    coated with a lubricating coating; and-   (IV) a production method of the above-mentioned guide wire by    inserting the tip end portion (a-2) portion into a tube with a    larger outer diameter than that of the tip end portion (a-2) and    injecting a resin raw material into the tube for resin-molding the    tip end portion (a-2) containing the (b) and then drawing out the    tip end portion (a-2) from the tube.    Best Modes of the Invention

With respect to the invention (I), the inner core (a) is composed of themain body portion (a-1) with a high rigidity and the tip end portion(a-2) smaller in diameter and lower in rigidity than the main bodyportion (a-1). A conventionally known material may be used as thematerial for composing the inner core (a) and examples of the materialinclude super elastic metallic bodies such as a stainless steel, a Ti—Nialloy, a Cu—Zn alloy, a Ni—Al alloy, a Cu—Zn—X alloy (X=Be, Si, Sn, Al,Ga and the like) and a preferable alloy is a stainless steel or a Ti—Nialloy and a more preferably alloy is a Ti—Ni alloy. The materialscomposing the main body portion (a-1) and the tip endportion (a-2) maybe similar or dissimilar to each other.

The outer diameter of the main body portion (a-1) of the inner core (a)is preferably 0.10 to 1.50 mm, more preferably 0.15 to 0.41 mm, andfurthermore preferably 0.25 to 0.31 mm. The length is preferably 500 to4,000 mm, more preferably 1,500 to 3,000 mm, and furthermore preferably1,800 to 2,500 mm. The buckling strength (the yield stress at the timeof load) is preferably 30 to 100 kg/mm² (22° C.) and more preferably 40to 55 kg/mm² (22° C.).

The outer diameter of the tip end portion of the inner core (a-2) issmaller than the outer diameter of the main body portion (a-1) andpreferably it becomes smaller toward the tip end. In this case, it ispreferable to carry out tapering and the outer diameter of the most tipend portion is preferably 0.01 to 0.1 mm and more preferably 0.02 to0.05 mm. The length is preferably 10 to 400 mm and more preferably 50 to300 mm. The bending load and the restoring load are preferably 0.1 to 10g and more preferably 0.3 to 6.0 g.

It ifs no need that the main part portion (a-1) and the tip end portion(a-2) have same restoring stress, or rather preferably they have properphysical properties with proper wire diameters by changing the thermaltreatment conditions. Further, the inner core (a) is not limited to asingle wire and maybe composed of a plurality of wires to have theabove-mentioned functions, that is, physical properties changing insteps or continuously.

The high x-ray contrast unit (b) is at the tip end of the inner core (a)and is a circular member of a metal having a high x-ray contrastingability and practically it is a coil-like or pipe-like member andpreferably it is a coil-like member. Examples of the metal having thehigh x-ray contrasting ability are gold, platinum, silver, bismuth,tungsten and the like and preferable examples are gold and platinum. Itis further preferable for the tip end portion (a-2) to have a furthertip end part in 10 cm or less, preferably 5 cm or less, in the lengthmade of gold or platinum. The unit (b) is preferable to cover the mainpart of the tip end portion (a-2) and therefore has a wider outerdiameter than the outer diameter of the tip end portion (a-2). That is,the outer diameter of the high x-ray contrast unit is preferably 0.1 to1.5 mm, more preferably 0.15 to 0.41 mm, and furthermore preferably 0.2to 0.31 mm. The inner diameter is preferably 0.04 to 1.4 mm, morepreferably 0.06 to 0.30 mm, and furthermore preferably 0.08 to 0.15 mm.The length is preferably 10 to 400 mm and more preferably 50 to 300 mm.

The guide wire of the invention comprises the tip end portion (a-2) ofthe inner core (a) which is resin-molded with the high x-ray contrastunit (b) included therein. The outer diameter of the portion formed byresin-molding is equal to or smaller than the outer diameter of the mainpart portion of the main part portion (a-1). The outer diameter maybeeither uniform at both ends of the tip end portion (a-2) or tapered tobe smaller toward the tip end portion. The uniform outer diameter ismore preferable.

The molded resin is not particularly limited if it is an elastomer andis not softened in the inside of a human body, and the tensile strengthof the elastomer is preferably 50 kg/cm² or higher, more preferably 100to 400 kg/cm 2, furthermore preferably 200 to 400 kg/cm². The 300%modulus is preferably 40 kg/cm or less, more preferably 5 to 30 kg/cm 2,and furthermore preferably 5 to 20 kg/cm². The elongation is preferably200% or higher and more preferably 300 to 1,000%. The measurementmethods of these properties are based on ASTM D412. The heat resistanceis preferably high enough to stand for continuous use at 60° C. orhigher. The wear resistance is preferably 0.1 to 0.3 and more preferably0.15 to 0.25, on the basis of the dynamic friction coefficient. The wearresistance is measured according to the following method.

(Evaluation Method of the Wear Resistance)

The wear resistance is evaluated on the basis of dynamic frictioncoefficient of the molded resin surface. The dynamic frictioncoefficient is measured by measuring that between a friction memberformed by bending a steel wire with a diameter of 0.5 mm and the resinsurface under the conditions of 20 g load and 1 mm/s speed by usingKES-FB-4 S manufactured by Kato-Tech. Co.

As the material for the elastomer, practically, at least one or moreelastomers selected from elastomer resins such as polyolefins(polyethylene, polypropylene, and the like), ethylene-vinyl acetatecopolymers, poly vinyl chloride, polyesters, polyamides, polyurethanes,polystyrene, epoxy resins, fluorocarbon resins, silicone resins, and/ortheir mixtures and compounded products can be exemplified. Preferableexamples are polyethylene, polyesters, polypropylene, polyurethanes,fluorocarbon resins, and silicone resins which are highly safe to thehuman body and more preferable examples are polyesters, polyurethanes,silicone resins, and fluorocarbon resins which have high elasticity andfurthermore preferable examples are polyurethanes with high wearresistance and adhesion strength.

As the raw materials (c) forming these elastomers, there arenon-reactive type (c-1) and reactive type (c-2) from another point ofview.

The non-reactive type (c-1) may preferably include those among theabove-mentioned elastomers having a weight average molecular weight of10,000 and 1, 000,000 and a softening point of 60° C. or higher. That ispreferable because if the molecular weight is in the above-mentionedrange, the elastomer is thermally fusible and moldable and if thesoftening point is 60° C. or higher, it is not softened in the humanbody temperature. The reactive type (c-2) is preferably oligomers orpolymers with a weight average molecular weight of 500 to 500,000 andmore preferably 1,000 to 300,000 and having functional groups at theterminals or side chains to be higher polymers by curing at the time ofmolding. The reactive type (c-2) is further preferably those havingfunctional groups at the terminals. That is because those having thefunctional groups at the terminals are excellent in the elongation ofthe resulting resins after curing as compared with those having thefunctional groups at the side chains. Examples of the functional groupsare those causing reaction at a normal temperature or by heating andpractical examples are isocyanate group (free, block type), epoxy group,unsaturated groups (double bond groups), amido group, hydroxyl,carboxylic acid group, sulfonic acid group, acid anhydride group, acidhalide group, a lower alkoxy group, amino group, diazonium group, azidegroup, aldehyde group, N-methylol group, iminocarbonic acid ester,silanol group, hydrolyzable silyl group [tri- or di-alkoxy (of 1 to 3carbon atoms) silyl] and the like. Those having one or more of thesefunctional groups in each molecule are preferable.

Among these functional groups, further preferable groups are functionalgroups causing additional reactions and examples are isocyanate group,epoxy group, hydroxyl group, N-methylol group, aldehyde group, and aminogroup (primary amino group and secondary amino group). In the case ofadditional reaction, no byproduct is produced by condensation, andtherefore, no foam remains in the molded product.

The types of the resins forming the skeleton of the reactive type (c-2)are those same as the resin described in the above explanation of theraw materials (c). Among the raw materials of the resins, preferableexamples are polyethylene, polyesters, polypropylene, polyurethanes,fluorocarbon resins, and silicone resins and more preferable examplesare polyesters, polyurethanes, silicone resins, and fluorocarbon resinsand furthermore preferable examples are polyurethanes.

Among the raw materials (c), the reactive type (c-2) is preferable. Thatis because in the case of a reactive type, a further higher molecularweight polymer is obtained by the reaction and no non-reactive lowmolecular weight polymer compound is left, so that a substance safe andharmless to a human body can be obtained. As the reactive type (c-2),those comprising the functional groups having addition reactivity in themolecular terminals as described above are preferable and particularly,so-called urethane prepolymers, urethane oligomers comprising functionalgroups in the terminals are preferable. Urethane oligomers can beobtained by reaction of polyisocyanates and polyols.

As the polyisocyanates, those having two or more isocyanate groups ineach molecule, more preferably 2 to 4 isocyanate groups, are preferableand practical examples are as follows. (I) Polyisocyanate diisocyanate(TDI); crude TDI; 2,4′-4,4′-diphenylmethane diisocyanate (MDI); crudeMDI; 4,4′-diisocyanatebiphenyl;3,3′-dimethyl-4,4′-diisocyanatebiphenyl;3,3′-dimethyl-4,4′-diisocyanatediphenylmethane;1,5-naphthylenediisocyanate; 4,4′,4″-triphenylmethanetoly isocyanate; m-and/or p-isocyanatephenylsulfonyl isocyanate; polyaryl polyisocyanate(PAPI), and the like:

(ii) Aliphatic polyisocyanates of 2 to 18 carbon atoms; ethylenediisocyanate, hexamethylene diisocyanate (HDI), tetramethylenediisocyanate, dodecamethylene diisocyanate, 1,6,11-undecanetriisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysinediisocyanate, 2,6-diisocyanatemethylcaproate, bis(2-isocyanateethyl)fumarate, bis(2-isocyanateethyl) carbonate,2-isocyanateethyl-2,6-diisocyanatehexanoate, trimethylhexamethylenediisocyanate (TMDI), and dimer acid diisocyanate (DDI), and the like.

(iii) Alicyclic polyisocyanates of 4 to 15 carbon atoms; isophoronediisocyanate (IPDI), dicyclohexyl diisocyanate, dicyclohexylmethanediisocyanate (H-MDI), cyclohexylene diisocyanate, hydrogenatedtolylenediisocyanate (HTDI),bis(2-isocyanateethyl)-4-cyclohexene-1,2-dicarboxylate, 2,5- and/or2,6-norbornanediisocyanate and the like.

(iv) Aromatic aliphatic polyisocyanates of 8 to 15 carbon atoms.-m-and/or p-xylenediisocyanate (XDI), a,a,a′,a′-tetramethylxylylenediisocyanate (TMXD) and the like.

(v) Modified compounds of the above-mentioned polyisocyanates;

modified products containing urethane group, carbodiimido group,allophanate group, urea group, biuret group, urethodione group,urethonimine group, isocyanurate group, or oxazolidone group; examplesof the modified compounds are polyol (the following low molecular weightand/or high molecular weight polyol) adducts of polyisocyanates [themole ratio of NCO/OH is preferably (1.01 to 10)/1 and more preferably(1.1 to 5)/1 and an adduct of trimethylolpropane 1 mole and theabove-mentioned diisocyanate 3 mole; an adduct of pentaerythritol andthe above-mentioned diisocyanate 4 mole.

(vi) Diisocyanate polymers; isocyanurates of the above-mentionedpolyisocyanate (trimers, pentamers), biurets of the above-mentioneddiisocyanates (trimers, pentamers) and the like. Two or more of thesepolymers may be used in combination. Among them, preferablepolyisocyanates are those belonging the groups (ii) and (iv) and morepreferably (ii) and furthermore preferably HDI.

Examples of polyols are those having preferably 2 or more and morepreferably 2 to 4 hydroxyl groups and practical examples arepolyalkylene ether polyol (1), polyester polyol (2), polymer polyol (3),polybutadiene polyol (4), castor oil-based polyol (5), acryl polyol (6),and mixtures of two or more of these polyols. The number averagemolecular weight of the polyols is generally 500 to 20,000, preferably500 to 10,000, and furthermore preferably 1,000 to 3,000.

Polyalkylene ether polyol (1), compounds obtained by adding alkyleneoxide (hereinafter abbreviated as AO) to active hydrogen atom-containingpolyfunctional group (D) and mixtures of two or more of these compoundscan be exemplified.

Examples of (D) are polyhydric alcohols (d-1), polyhydric phenols (d-2),amines (d-3), polycarboxylic acids (d-4), phosphoric acids (d-5),polythiols (d-6) and the like. alcohols such as ethylene glycol,propylene glycol, 1,3-butylene glycol, 1,4-butanediol, 1,6-hexanediol,diethylene glycol, neopentyl glycol, bis(hydroxymethyl)cyclohexane, andbis (hydroxyethyl) benzene; and poly hydric (tri- to octa-hydric)alcohols such as glycerin, trimethylolpropane, pent aerythritol,diglycerin, a-methyl glucoside, sorbitol, xylitol, mannitol,dipentaerythritol, glucose, fructose, sucrose and the like.

Examples of polyhydric phenols (d-2) are polyhydric phenols such aspyrogallol, catechol, and hydroquinone and in addition to them,bisphenols such as bisphenol A, bisphenol F,

Examples of polyhydric alcohols (d-1) are dihydric bisphenol S and thelike.

Examples of amines (d-3) are monoamines such as ammonia, alkylamines of1 to 20 carbon atoms (butylamine), and aniline; aliphatic polyaminesethylenediamine, trimethylenediamine, hexamethylenediamine, anddiethylenetriamine; piperazine, N-aminoethylpiperazine and heterocyclicpolyarines described in Japanese Patent Application Publication No.55-21044; alicyclic polyamines such as dicyclohexylmethanediamine, andisophoronediamine; aromatic polyamines such as phenylenediamine,tolylenediamine, diethyltolylenediamine, xylylenediamine,diphenylmethanediamine, diphenyletherdiamine, andpolyphenylmethanepolyamine; and alkanolamines such as monoethanolamine,diethanolamine, triethanolamine, triisopropanolamine, and the like.

Examples of polycarboxylic acids (d-4) are aliphatic polycarboxylicacids such as succinic acid and adipic acid and aromatic polycarboxylicacids such as phthalic acid, terephthalic acid, and trimellitic acid.

Examples of phosphoric acids (d-5) are phosphoric acid, phosphorousacid, phosphonic acid, and mono- or dialkyl (1 to 10 carbon atoms)esters of them. Examples of polythiols (d-6) are polyhydricthiolcompounds obtained by reaction of glycidyl-containing compounds andhydrogen sulfide. Two or more kinds of the above-mentioned activehydrogen atom-containing compounds (D) can be used.

As AO to be added to the (D), ethylene oxide (EO), propylene oxide (PO),1,2-, 2,3-, or 1,3-butylene oxide, tetrahydrofuran (THF), styrene oxide,a-olefin oxide, epichlorohydrin and the like.

AO may be used solely or two or more may be used in combination and inthe latter case, block-addition (tipped type, balanced type, activesecondary type and the like) or random-addition or their mixed system[those tipped after random addition; those having 0 to 50% by weight (5to 50% by weight) of ethylene oxide chains distributed randomly inmolecule and tipped with EO chains 0 to 30% by weight (preferably 5 to25% by weight) at the molecular terminals may be used. Among the aboveexemplified A0, preferable examples are solely E0, solely P0, solelyTHF, a combination of PO and E0, and a combination of THF with PO and/orEO (in the case of combination, random, block and mixed system of them).

The addition of AO to (D) can be carried out by a common method and inthe absence or in the presence of a catalyst (an alkali catalyst, anamine type catalyst, an acidic catalyst, a metal complex catalyst andthe like), it is carried out at a normal pressure or a pressurizedcondition (especially in the latter half of the AO addition step) in onestep or multi-steps. Further, the polyalkylene ether polyol (1) mayinclude those having a further increased molecular weight by furtherreaction with a small ratio [equivalent ratio of polyalkylene etherpolyol/polyisocyanate: preferable (1.2 to 10)/1, more preferably (1.5 to2)/1] of a polyisocyanate (which will be exemplified later).

The equivalent of the polyalkylene ether polyol (1) (the molecularweight per hydroxyl group) is preferably 100 to 10,000, more preferably250 to 5,000, and furthermore preferably 500 to 1,500. Further, thefunctionality value of the polyalkylene ether polyol (1) is preferably 2to 8, more preferably 2 to 3, and furthermore preferably 2. Theunsaturated degree of the polyalkylene ether polyol (1) is preferablylow, more preferably 0.1 meq/g or lower, more preferably 0.05 meq/g orlower, and furthermore preferably 0.02 meq/g or lower. The content ratioof primary hydroxyl group of the polyalkylene ether polyol (1) ispreferably 0 to 100%, more preferably 30 to 100%, furthermore preferably50 to 100%, and most preferably 70 to 100%.

Examples of the polyester polyol (2) include condensed polyester diolsobtained by reaction of low molecular weight diols and/or polyalkyleneether diols having a molecular weight of 1,000 or less with dicarboxylicacids; polylactonediols obtained by ring-opening polymerization oflactone; and polycarbonate diols obtained by reaction of carbonic aciddiesters with low molecular weight diols and lower alcohols (methanol orthe like).

Examples of the above-mentioned low molecular weight diols includeethylene glycol, diethylene glycol, propylene glycol, dipropyleneglycol, 1,4-, 1,3-butanediol, neopentyl glycol, 1,6-hexanediol; lowmolecular weight diols having cyclic groups [e.g. those described inJapanese Patent Application Publication No. 45-1474;bis(hydroxymethyl)cyclohexane, bis (hydroxyethyl) benzene, bisphenolA-ethylene oxide adduct] and mixtures of two or more of them.

Examples of polyalkylene ether diols with a molecular weight of 1,000 orless include polytetramethylene ether glycol, polypropylene glycol,polyethylene glycol, and mixture of two or more of these glycols.

Further, examples of dicarboxylic acid include aliphatic dicarboxylicacid (succinic acid, adipic acid, azelaic acid, sebacic acid and thelike), aromatic dicarboxylic acid (terephthalic acid, isophthalic acid,phthalic acid and the like), and ester-forming derivatives of thesedicarboxylic acids [acid anhydrides, lower alkyl (1 to 4 carbon atoms)esters] and mixtures of two or more of them and examples of lactoneinclude E-caprolactone, y-butylolactone, y-valerolactone, and mixturesof two or more of them. Polyesterification may be carried out by anormal method, for example, by reaction (condensation) of low molecularweight diols and/or polyether diols having a molecular weight 1,000 orlower with dicarboxylic acid or their ester-formable derivatives [e.g.anhydrides (maleic anhydride and phthalic anhydride), lower esters(dimethyl adipate and dimethyl terephthalate), halides] or theiranhydride and alkylene oxide (e.g. ethylene oxide and/or propyleneoxide) or adding lactone to imitators (low molecular weight diols and/orpolyether diols having a molecular weight 1,000 or lower).

Practical examples of these polyester polyols (2) are polyethyleneadipate diol, polybutylene adipate diol, polyhexamethylene adipate diol,polyneopentyl adipate diol, polyethylenepropylene adipate diol,polyethylenebutylene adipate diol, polybutylenehexamethylene adipatediol, polyethylene adipate diol, poly(polytetramethylene ether) adipatediol, polyethylene azelate diol, polyethylene sebacate diol,polybutylene azelate diol, polybutyrene sebacate diol, polycaprolactonediol or triol, polyhexamethylene carbonate diol.

Examples of the polymer polyol (3) include those obtained bypolymerizing radical polymerizable monomers [e.g. styrene,(meth)acrylonitrile, (meth) acrylic acid esters, vinyl chloride, andmixtures of two or more of them] in polyols (the above-mentionedpolyalkylene ether polyols and/or polyester polyols) and dispersing theobtained polymers.

In general, polymerization initiators are used for polymerizing thesemonomers. As the polymerization initiators, azo compounds for producingradical groups for starting polymerization such as2,2′-azobisisobutyronitrile (AIBN),2,2′-azobis-(2,4-dimethylvaleronitrile) (AVN); dibenzoyl peroxide,dicumyl peroxide, peroxides described in Japanese Patent ApplicationLaid-Open No. 61-76517 other than those described above, persulfates,perborates, and persuccinic acid can be used and practically azocompounds, particularly AIBN and AVN are preferable. The use amount ofthe polymerization initiators is preferably 0.1 to 20% by mass and morepreferably 0.2 to 10% by mass on the basis of the full amount of themonomers.

The polymerization reaction in polyols can be carried out without asolvent, however in the case of a high polymerization concentration, itis preferable to carry out in the presence of an organic solvent. As thesolvent, for example, benzene, toluene, xylene, acetonitrile, ethylacetate, hexane, heptane, dioxane, N,N-dimethylformamide,N,N-dimethylacetamide, isopropyl alcohol, and n-butanol are exemplified.Further, the polymerization can be carried out in the presence of knownchain transfer agents except for alkylmercaptans (tetrachlorocarbon,tetrabromocarbon, chloroform, enol ethers described in Japanese PatentApplication Laid-Open No. 55-31880) based on the necessity.

The polymerization can be carried out in a batch mode or a continuousmode. The polymerization reaction can be carried out at a temperatureequal to or higher than the decomposition temperature of thepolymerization initiators, preferably 60 to 180° C., more preferably 90to 160° C., further preferably 100 to 150° C. under the atmosphericpressure or pressurized condition or vacuum condition.

On completion of the polymerization reaction, the obtained polymerpolyols may be used as they are for polyurethane production withoutadding any post-treatment, however it is preferable to remove theorganic solvents, the decomposition products of the polymerizationimitators and impurities of the un-reacted monomers by conventionalmeans after the completion of the reaction.

Examples of the polymer polyol (3) obtained in such a manner preferablyinclude semi-transparent or opaque white or yellowish brown colordispersions comprising the entire monomers of which 30 to 70%,preferably 40 to 60%, further preferably 45 to 55%, most preferably 50to 55%, that is, polymers, dispersed in polyols. The hydroxyl value ofthe polymer polyols (3) is preferably 10 to 300, more preferably 20 to250, and furthermore preferably 30 to 200.

The polybutadiene polyol (4) includes those having 1,2-vinyl structure,1,2-vinyl structure and 1,4-trans structure, and 1,4-trans structure.The ratio of the 1,2-vinyl structure and 1,4-trans structure on thebasis of mole can be changed variously, for example, (100:0) to (0:100).The polybutadiene glycol (4) further includes homopolymers andcopolymers (styrene butadiene copolymers, acrylonitrile butadienecopolymers, and the like) and their hydrogenated ones (hydrogenationratio: for example 20 to 1000). The number average molecular weight ofthe polybutadiene glycol (4) is preferably 500 to 10,000.

Practical examples of the polybutadiene glycol (4) include those havingthe following general formulas (1) to (3): HO—C—C—CV-C— (C—CV)n-C—CV-C—C—OH (1), OH-[(C—C═C—C)_(a)(C-CV)_(c)(C—C═C—C)b]_(n)—OH (2),and OH-[(C—C═C—C)_(a)(CX—C)_(b)]_(n)—OH (3) [wherein —C— denotes —CH2—;—C═C— denotes —CH═CH—; —CV- denotes —C(CH═CH2) H—; and —CX— denotes—C(X)H—; and X denotes phenyl or nitrile group].

The polybutadiene glycols defined by the general formula (1) are, forexample, those given in the case n is 15 to 80; the polybutadieneglycols defined by the general formula (2) are, for example, those givenin the case n is 50 to 55, a is 0, 2, b is 0.6, and C is 0.2; and thepolybutadiene glycols defined by the general formula (3) are, forexample, those given in the case n is 78 to 87, a is 0,75, and b is0.25.

Commercialized products defined by the general formula (1) are NISSO-PBG series (products manufactured by Nippon Soda Co., Ltd. andpractically, G-1000, G-2000, and G-3000 can be exemplified.Commercialized products defined by the general formulas (2) and (3) arePoly Bd (products of US ARCO) and practically, Poly Bd R-45M, R-45HT,CS-15, and CN-15 can be exemplified.

The castor oil-based polyol (5) includes castor oil and modified castoroil (caster oil modified by polyhydric alcohols such as trimethylolpropane, pentaerythritol).

The ratio of the hydroxyl of the polyol and isocyanate of polyisocyanateon the basis of mole is preferably (1:2) to (2.:1), more preferably(1:1.5) to (1.5:1), furthermore preferably (1:1.2) to (1.2:1).

If the hydroxyl group is excess, prepolymers having hydroxyl groups atterminals are obtained and if the isocyanate group is excess, isocyanategroup-terminated urethane prepolymers are obtained. Further, based onthe necessity, the polymers may contain an urethanization promotingcatalyst, a filler, a plasticizer, an antioxidant, an UV absorbent andthe like.

The mixing ratio of the urethanization promoting catalyst is preferably0 to 10% by mass and more preferably 0.01 to 5% by mass in the entireurethane polymer. The mixing ratio of the filler_is preferably 5 to 50%by mass and more preferably 10 to 30% by mass. The mixing ratio of theantioxidant is preferably 0.001 to 10% by mass and more preferably 0.01to 5% by mass. The mixing ratio of the UV adsorbent is preferably 0.001to 10% by mass and more preferably 0.01 to 5% by mass.

Examples of the urethanization promoting catalyst are tin type catalystssuch as trimethyltin laurate, trimethyltin hydroxide, dimethyltindilaurate, dibutyltin diacetate, dibutyltin dilaurate, stanous octoate,and dibutyltin maleate; lead type catalysts such as lead oleate, lead2-ethylhexanate, lead naphthenate, and lead octanate; naphthenic acidmetal salts such as cobalt naphthenate, phenylmercuryl propionate;triethylenediamine, tetramethylethylenediamine,tetramethylhexylenediamine, diazabicycloalkenes; and amine typecatalysts and their organic acid salts (formic acid salt and the like)such as dimethylaminoethylamine, dimethylaminopropylamine,diethylaminopropylamine, dibutylaminoethylamine,dimethylaminooctylamine, dipropylaminopropylamine,2-(1-aziridinyl)ethylamine, 4-(1-piperidinyl)-2-hexylamine,N-methylmorpholine, N-ethylmorpholine, triethylamine,diethylethanolamine, dimethylethanolamine; and mixtures of two or moreof them. The addition ratio of the urethanization promoting catalyst inthe invention is preferably 0 to 10% by mass and more preferably 0.01 to5% by mass in the entire urethane prepolymer.

Examples of the filler is clay, heavy calcium carbonate, calciumcarbonate surf ace treated with fatty acid, barium sulfate, alumina,silica, carbon black, calcium oxide, titanium oxide, diatomaceous earth,glass fiber and its crushed substances (cut glass, milledglass, glassflakes and the like), shirasu-balloon, carbon fiber, potassium titanate,boron fiber, gypsum fiber, talc, mica, wollastonite, calcium silicate,chalk, glass beads, and quartz. The addition ratio of the filler ispreferably 5 to 50% by mass and more preferably 10 to 30 o by mass inthe entire I injection type uretha i4 resin composition.

Examples of the plasticizer are phthalic acid ester-based plasticizers(dibutyl phthalate, dioctyl phthalate and the like); phosphoric acidtriester type plasticizers (triphenyl phosphate, tricresyl phosphate andthe like); aliphatic dibasic acid esters type plasticizers [dibutylsebacate, dioctyl adipate, di(2-ethylhexyl) adipate, polyethylene glycol(molecular weight: 200) diadipate, and the like]; fatty acid ester typeplasticizers (methyl acetyl ricinolate and the like); polyester typeplasticizers (adipic acid-propylene glycol esters and the like);polyhydric alcohol type plasticizers (triethylene glycol dibenzoate andthe like); citric acid ester type plasticizers (triethyl citrate and thelike); and petroleum resin type plasticizers and the like. The additionratio of the plasticizer is preferably 5 to 70% by mass and morepreferably 15 to 50% by mass.

Examples of the antioxidant are hindered phenol type antioxidants[Irganox 1010 (Ciba-Geigy Corp.), octadecyl⁻ 3⁻(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Irganox 1076manufactured by Ciba-Geigy Corp.) and the like]; hindered amine typeantioxidant [(Sanol LS 770 manufactured by Sankyo Co., Ltd.), 4⁻benzoyloxy-2,2,6,6-tetramethylpiperidine (Sanol LS 744 manufactured bySankyo Co., Ltd.) and the like]. The addition amount of the antioxidantis preferably 0.001 to 10% by mass and more preferably 0.01 to 5% bymass.

Examples of the UV adsorbent are triazole type UV adsorbents[2-(5-methyl-2-hydroxyphenyl) benzotriazole and Tinuvin 320 (Ciba-GeigyCorp.) and the like]; benzophenone type UV adsorbent[2-hydroxy-4-methoxybenzophenone, Cyasorb UV 9 (manufactured by CyanamidLtd.) and the like]. The addition amount of the UV adsorbent ispreferably 0.001 to 10% by mass and more preferably 0.01 to 5% by mass.The method of producing the urethane prepolymer is not particularlylimited and, for example, a prepolymer method by producing an isocyanategroup-terminated prepolymer by carrying out reaction of a polyol and anexcess amount of a polyisocyanate at 50 to 120° C., preferably 70 to100° C. and successively carrying out reaction of the prepolymer and alow molecular weight diol and a one-shot method by carrying out a polyolcompound obtained by mixing a polyol and a low molecular weight diolwith a polyisocyanate. The reaction with polyisocyanate is carried out,for example, by a method of measuring the respective components andstirring the respective components; and a method by measuring thecomponents with a quantitative pump, fiercely mixing and stirring thecomponents, pouring to a butt, causing reaction at 80 to 200° C.,preferably 120 to 160° C., and pulverizing the obtained product.Further, the prepolymer can be produced by supplying the above-mentionedraw materials to an extruder at 80 to 260° C., preferably 120 to 250°C., polymerizing the raw materials while kneading and transporting theraw materials in the extruder, and then extruding the produced productout of a die.

An elastomer can be obtained by a urethane prepolymer by causingreaction as follows: it can be obtained by reaction of the obtainedisocyanate group-terminated urethane prepolymer and a low molecularweight polyol or polyamine; reaction of a hydroxyl group-terminatedurethane prepolymer and the above-mentioned polyisocyanate; or reactionunder the reaction conditions of the case of molding a mixture of ahydroxyl group-terminated urethane prepolymer and amino resin. Themixing ratio is preferably 1: (0.5 to 2), more preferably 1 (0.7 to 1.5)by mole ratio of the functional groups to be reacted. The reactiontemperature is preferably 50 to 180° C. and more preferably 80 to 160°C. The reaction period is preferably 1 to 20 hours. The reaction can bechecked by measuring the quantity of a functional group such asisocyanate group, hydroxyl, or the like by an isocyanate contenttitration analysis, IR analysis, or NMR analysis. Preferably, the momentof the completion is at the time when the terminal functional quantitybecomes zero.

The amino resin to be used in that case may include, for example,alkyl-(1 to 8 carbon atoms) etherified melamine resin, alkyl-(1 to 8carbon atoms) etherified benzoguanamine resin, alkyl-(1 to 8 carbonatoms) etherified urea resin, spiroguanamine resin, alkyl-(1 to 8 carbonatoms) etherified resin of diguanamine comprising two triazine ringsbonded to a phenylene core and/or mixtures of two or more of them. Amongthem, preferable examples are alkyl etherified melamine resin,alkyl-etherified benzoguanamine resin, and a more preferable example isalkyl-etherified benzoguanamine resin.

The hydroxyl group-terminated urethane prepolymer can be reacted with asilane coupling agent. For example, an exchange reaction of alkoxy-(1 to3 carbon atoms) silyl group and hydroxyl group is caused or reactionwith hydroxyl group after silanol group production can be carried out.In the case of an epoxy group-containing silane coupling agent, anelastomer is formed by reaction of the epoxy group with the hydroxylgroup. In the case of an epoxy group-terminated urethane prepolymer andan amino group-containing silane coupling agent, which will be describedlater, both amino group and alkoxysilyl group are reacted with the epoxygroup, so that they are efficient for elastomer formation.

As such a silane coupling agent, alkoxy-(1 to 3 carbonatoms)silyl-containing silane coupling agents are preferable andexamples of them are vinyl group-containing silane coupling agents(y-aminopropyltrimethoxysilane), epoxy group-containing silane couplingagents (y-glycidoxypropyltrimethoxysilane and the like),mercapto-containing silane coupling agents(y-mercaptopropyltrimethoxysilane and the like), amino group-containingsilane coupling agents (y-aminoipropyltrimethoxysilane and the like) andthe like and preferable examples are the epoxy group-containing silanecoupling agents and the amino group-containing silane coupling agents.The reaction conditions maybe same as described above.

Further, functional groups different from those mentioned above may beintroduced into the terminals of the urethane prepolymers. For example,as epoxy group-containing urethane elastomers, they can be produced by amethod of introducing epoxy groups into the terminals by reaction ofisocyanate groups of the isocyanate group-terminated urethane prepolymerwith hydroxyl-containing epoxy compound such as glycidol; or a method ofintroducing epoxy groups by reaction of the hydroxyl group-terminatedurethane prepolymer with epihalohydrin such as epichlorohydrin,epibromohydrin and the like. The amino-terminated urethane prepolymercan be obtained by reaction of isocyanate groups of the isocyanategroup-terminated urethane prepolymer and an excess amount of a diamine.

Elastomers can be obtained by using the epoxy group-terminated urethaneprepolymer and an epoxy resin curing agent. In such a case, anepoxylation reaction catalyst, a plasticizer, a curing promoting agentmay be used.

Examples of epoxy resin curing agent are aliphatic amines such asethylenediamine, diethylenetriamine, triethylenetetramine,xylylenediamine and the like; alicyclic amines such as4,4′-diaminobiscyclohexylmethane, isophoronediamine, hydrogenatedxylylenediamine and the like; aromatic amines such as aniline,dimethylaniline, diaminodiphenylmethane, phenylenediamine and the like;carboxylic acids and their anhydrides such as phthalic acid anhydride,hexahydrophthalic acid, tetrahydrophthalic acid and the like; BF₃complexes; dicyanediamides; and imidazoles and the like. Examples of theepoxylation reaction catalyst are benzyldimethylamine,dimethylcyclohexylamine, dimethylethanolamine, triethylamine,tributylamine, trimethylamine, BF3-monomethylamine complex, BF3-benzylamine complex, BF3-piperazine complex, BF3-aniline complex, aluminumisopropoxide and the like.

The amount of the epoxylation reaction catalyst to be used is 0.1 to 1%by mass and preferably 0.1 to 0.5% by mass in the entire resincomposition.

Examples of the plasticizer are those exemplified above and the amountto be used may be also same.

Examples of a curing promoting agent are phenol, cresol, nonylphenol,styrene-reacted phenol, resorcinol, xylenol, salicylic acid, tertiaryamine, trisdimethylaminomethylphenol and the like.

The method of producing the urethane elastomer from the epoxygroup-containing urethane prepolymer is not particularly limited, andthe epoxy group-containing urethane prepolymer, an epoxy curing agent,and if necessary, an epoxylation reaction catalyst are mixed, enclosedin a container, heated at 100 to 200° C., preferably 120 to 180° C. forseveral hours for reaction to obtain a half-cured resin which is thenfurther cured for several hours to 10 days to obtain a completely curedresin.

Further, the epoxy group-containing urethane prepolymer may becross-linked by reaction of it with polyols or thiols. The hydroxylgroup-terminated urethane prepolymer may be cured by reaction ofcarboxyl group-terminated or acid anhydride-terminated urethaneprepolymer with epoxy resin.

The epoxy resin is not particularly limited if the resin has two or moreepoxy groups in a molecule and the following types (1) to (5) can beexemplified. The mixing ratio by mole of the hydroxyl groups and epoxygroups is preferably 1: (0.5 to 2) and more preferably 1:(0.7 to 1.5).(1) Glycidyl ether type:

-   (i) glycidyl ethers of dihydric phenols;-   diglycidyl ethers of dihydric phenols of 6 to 30 carbon atoms, such    as bisphenol F diglycidyl ether, bisphenol A diglycidyl ether,    bisphenol B diglycidyl ether, bisphenol AD diglycidyl ether,    bisphenol S diglycidyl ether, halogenated bisphenolA diglycidyl    ether, tetrachlorobisphenol A diglycidyl ether, catechin diglycidyl    ether, resorcinol diglycidyl ether, hydroquinone diglycidyl ether,    1,5-dihydroxynaphthalene diglycidyl ether, dihydroxybiphenyl    diglycidyl ether, octachloro-4,4′-dihydroxybiphenyl diglycidyl    ether, tetramethylbiphenyl diglycidyl ether,    9,9′-bis(4-hydroxyphenyl)fluorene diglycidyl ether, and diglycidyl    ether obtained by reaction of bisphenol A 2 moles and    epichlorohydrin 3 moles;-   (ii) polyglycidyl ethers of tri- to hexa- or higher hydric,    polyhydric phenols; polyglycidyl ethers of tri- to hexa- or higher    hydric, polyhydric phenols of 6 to 50 carbon atoms or more and    having 110 to 3,000 molecular weights, such as pyrogallol    triglycidyl ether, dihydroxynaphthylcresol triglycidyl ether, tris    (hydroxyphenyl) methane triglycidyl ether, dinaphthyltriol    triglycidyl ether, tetrakis(4-hydroxyphenyl)ethane tetraglycidyl    ether, p-glycidylphenyldimethyltriol bisphenol A glycidyl ether,    trismethyl-teit-butyl-butylhydroxymethane triglycidyl ether,    4,4′-oxybis(1,4-phenylethyl)tetracresol glycidyl ether,    4,4′-oxybis(1,4-phenylethyl)phenyl glycidyl ether, bis    (dihydroxynaphthalene) tetraglycidyl ether, glycidyl ethers of    phenol or cresol novolak resins (molecular weight of 400 to 3,000);    glycidyl ether of limonene phenol novolak resins (molecular weight    of 400 to 3,000); polyglycidyl ethers of polyphenols (molecular    weight of 400 to 3,000) obtained by condensation reaction of phenol    and glyoxal, glutaraldehyde, or formaldehyde; polyglycidyl ethers of    polyphenol with a molecular weight of 400 to 3,000 obtained by    condensation reaction of resorcin and acetone;-   (iii) diglycidyl ether of aliphatic dihydric alcohols;-   diglycidyl ethers of diols of 2 to 100 carbon atoms and having a    molecular weight of 62 to 3, 000, such as ethylene glycol diglycidyl    ether, propylene glycol diglycidyl ether, tetramethylene glycol    diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyethylene    glycol (molecular weight of 150 to 3,000) diglycidyl ether,    polypropylene glycol (molecular weight of 180 to 3,000) diglycidyl    ether, polytetramethylene ether glycol (molecular weight of 200 to    3, 000) diglycidyl ether, neopentyl glycol diglycidyl ether,    diglycidyl ethers of AO [EO or PO (1 to 20 moles)] adduct of    bisphenol A; and-   (iv) polyglycidyl ethers of tri- to hexa- or higher hydric aliphatic    alcohols; glycidyl ethers of tri- to hexa- or higher hydric    polyhydric alcohols of 3 to 50 or more carbon atoms and having a    molecular weight of 76 to 3,000, such as trimethylolpropane    triglycidyl ether, glycerin triglycidyl ether, pentaerythritol    tetraglycidyl ether, sorbitol hexaglycidyl ether, and poly(n=2 to 5)    glycerol polyglycidyl ethers. (2) Glycidyl ester type:-   diglycidyl esters of di-. to hexa- or higher aromatic polycarboxylic    acids of 6 to 20 or more carbon atoms and diglycidyl esters of di-    to hexa- or higher aliphatic or alicyclic polycarboxylic acids of 6    to 20 or more carbon atoms;-   (i) as glycidyl esters of aromatic polycarboxylic acids, examples    are glycidyl esters of phthalic acids such as phthalic acid    diglycidyl ester, isophthalic acid diglycidyl ester, terephthalic    acid diglycidyl ester, and trimellitic acid triglycidyl ester; and-   (ii) as glycidyl esters of aliphatic or alicyclic polycarboxylic    acids, examples are the esters obtained by hydrogenation of the    aromatic cores of the above-mentioned phenol type glycidyl esters,    dimer acid diglycidyl esters, diglycidyl oxalate, diglycidyl    maleate, diglycidyl succinate, diglycidyl glutarate, diglycidyl    adipate, diglycidyl pimelate, glycidyl (meth)acrylate (co)polymer    (polymerization degree, for example, 2 to 10), tricarballylic acid    triglycidyl esters; (3) Glycidylamine type:-   glycidylamines of aromatic amines of 6 to 20 or more carbon atoms    and having 2 to 10 or more active hydrogen atoms and glycidylamines    of aliphatic, alicyclic or heterocyclic amines;-   (i) as the glycidylamines of the aromatic amines, examples are    N,N-diglycidylaniline, N,N-diglycidyltoluidine,    N,N,N′,N′-tetraglycidyldiaminodiphenylmethane,    N,N,N′,N′-tetraglycidyldiaminodiphenylsulfone,    N,N,N′,N′-tetraglycidyldiethyldiphenylmethane, and    N,N,O-triglycidylaminophenol;-   (ii) as the glycidylamines of aliphatic amines, examples are    N,N,N′,N′-tetraglycidylxylylenediamine and    N,N,N′,N′-tetraglycidylhexamethylenediamine;-   (iii) as the glycidylamines of alicyclic amines, examples are    hydrogenated compounds of N,N,N′,N′-tetraglycidylxylylenediamine;    and-   (iv) as the glycidylamines of heterocyclic amines, an example is    trisglycidylmelamine.-   (4) Aliphatic epoxides:-   aliphatic di- to hexa- or higher epoxides of 6 to 50 or more carbon    atoms, such as epoxylated polybutadiene (molecular weight 170 to    3,000) with epoxy equivalent of 130 to 1,000 and epoxylated soybean    oil (molecular weight 170 to 3,000).-   (5) Alicyclic epoxides:-   alicyclic epoxides of 6 to 50 or more carbon atoms having a    molecular weight of 98 to 3,000 and comprising 2 to 4 or more epoxy    groups, such asvinyl cyclohexene dioxide, limonene dioxide,    dicyclopentadiene dioxide, bis(2,3-epoxycyclopentyl) ether,    ethyleneglycol bis(epoxydicyclopentyl) ether,    bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, and    bis(3,4-epoxy-6-methylcyclohexylmethyl)butylamine; epoxides obtained    by hydrogenation of the cores of epoxy compounds of the    above-mentioned phenols. Compounds other than those exemplified (1)    to (5) maybe usable if they are epoxy resins comprising active    hydrogen and reactive glycidyl groups. Two or more of these    polyepoxides and monoepoxides can be used in combination.

Among them, preferable examples are diglycidyl ethers of dihydricphenols (6 to 30 carbon atoms); polyglycidyl ethers of tri- to hexa- orhigher hydric polyhydric phenols (6 to 50 carbon atoms) and furtherpreferable examples are diglycidyl ethers of dihydric phenols (6 to 30carbon atoms).

As described, a variety of functional groups can be introduced into theterminals of urethane polymers and elastomers can be produced by curingby various reactions. The reactions may be reactions other thandescribed above. Among them, reaction by thermosetting is preferable andaddition reaction with no solvent and volatile components is furthermorepreferable. As the urethane polymers formed by such a reaction, urethaneprepolymers to be supplied for molding materials are preferable. Thereare many commercialized products of urethane prepolymers and forexample, Monotan (reaction type urethane prepolymer: manufactured byCompounding Ingredients Ltd.), Sanprene (reaction type and non-reactiontype urethane prepolymer; manufactured by Sanyo Chemical Industries,Ltd.), and the like.

A production method of the guide wire of the invention include a methodfor resin-molding a tip end portion (a-2) of a guide wire comprising aninner core (a) composed of a main part portion (a-1) with a highrigidity and the tip end portion (a-2) smaller in diameter and lower inrigidity and integrally formed with the (a-1) and a high x-ray contrastunit (b) formed in the tip end portion (a-2), wherein the guide wire isproduced by inserting the tip end portion (a-2) portion into a tube witha larger outer diameter than that of the tip end portion (a-2) andinjecting a resin raw material into the tube for resin-molding the tipend portion (a-2) containing the high x-ray contrast unit (b) and thendrawing out the tip end portion (a-2) from the tube.

At first, as the pretreatment for inserting the tip end portion (a-2)portion into the tube with a larger outer diameter than that of the tipend portion (a-2), it is preferable that the inner core and the highx-ray contrast unit (b) are washed with a solvent such as an alcohol(methanol, ethanol, isopropanol and the like), a ketone (acetone, methylethyl ketone, and the like), an ester (ethyl acetate, butyl acetate, andthe like) for washing out adhering impurities and oils. Preferably, thewashing may be carried out by immersion, stirring or spraying treatmentat 10 to 100° C. for 10 minutes to 10 hours.

Further, the inner core (a) is preferably treated with a primer. As theprimer, known primers may be used and those excellent in the adhesion tothe metals composing the inner core (a) and the high x-ray contrast unit(b) are preferable. Particularly, the primer is preferable to haveelasticity as same as the above-mentioned elastomer. Practical examplesto be used as such a primer are materials same as the prepolymersexemplified above as the resin raw materials for the elastomers ofolefin type, urethane type, epoxy type, acrylic type, latex and the likeand in addition, cyanoacrylate type adhesive, silane coupling agent andthe like can be used. As the practical examples, commercialized productssuch as ADEKA BONTIGHTER HUX-350 (water-based urethane resin:manufactured by AsahiDenka Kogyo K.K.), Silbond 49SF (manufactured byCompounding Ingredient Ltd.), Mitec NY-T-36 (NCO-containing urethaneresin: manufactured by Mitsubishi Chemical Corporation), and Polytail HE(polyolefin resin: manufactured by Mitsubishi Chemical Corporation) canbe exemplified.

Depending on the types of primers to be used, the primer treatmentdiffers, and an example of the treatment method is carried out byimmersing the inner core (a) and the high x-ray contrast unit (b) in aprimer solution, or spraying or applying the primer solution to theinner core (a) and the high x-ray contrast unit (b); drying out thesolvent used for diluting the primer at a normal temperature for 1 hourto overnight, and heating the resulting the inner core (a) and the highx-ray contrast unit (b) preferably at 50 to 200° C., more preferably 80to 150° C., for 1 to 12 hours. The primer is preferably diluted based onnecessity so as to use the primer with an adjusted concentration andviscosity. The concentration is preferably 0.1 to 10% by weight and theviscosity is preferably 1 to 200 mPa·s. The dried film thickness of theprimer is preferably 0.05 to 30 μm and more preferably 0.15 to 10 μm.

The production method of the guide wire to be carried out aftercompletion of such treatment will be described along with FIG. 1. Theinner core 1 is inserted into a tube 4 made of resin with a length about3 times as long as that of the tip end portion 2 so as to push the innercore 1 in such a manner that the most tip end of the inner core 1 is ata point of 2 to 10 cm from the outlet of the resin tube 4. The tip endof the resin tube 4 is extruded by about 2 to 10 cm from the tip endportion 2. The inner diameter of the resin tube 4 is same as the outerdiameter of the inner core. The outer diameter of the resin tube 4 ispreferably 0.5 to 1 mm. If the outer diameter of the inner core 1 is0.31 mm, the inner diameter of the resin tube 4 is 0.31 mm and the outerdiameter is 1 mm and if the outer diameter of the inner core 1 is 0.25mm, the inner diameter of the resin tube 4 is 0.25 mm and the outerdiameter is 1 mm. The material for the resin tube 4 is not particularlylimited if it can be swollen with a solvent to be used later and forexample, fluorocarbon, urethane, silicone, or olefin resins may be used.

The tip end part of the resin tube 4 is inserted into a tube 5 made of ametal (e.g. a stainless steel). The metal tube 5 is adjusted to haveapproximately same length as that of the tip end portion 2 of the innercore. The gap between the resin tube 4 and the metal tube 5 is sealed bya sealing member 6. The sealing member 6 is preferably urethane,fluorocarbon, or silicone rubber with elasticity, easy to handle, andfurther preferably it is made of the material same as the resin tube 4.That is because elastomers can be prevented from entering the gapbetween the metal tube 5 and the resin tube 4 and adhering to the resintube 4 and thereby polluting the inner core and deteriorating theworkability in the step thereafter.

The above-mentioned elastomer raw material (e.g. urethane prepolymer andits blends) is melted to have a melt viscosity of preferably 200 mPa·sor less and while the metal tube 5 being in the lower side, the meltedelastomer is injected through the inlet of the resin tube 4 up to thetaper boundary (around the upper part of 2). As the injection method, amethod of injecting the elastomer up to the taper boundary based on thecapillary phenomenon by keeping the metal tube 5 in the lower side andimmersing it in the melted elastomer or a method of slowly filling theportion up to the taper boundary of the resin tube 4 with the elastomerby reducing the pressure from the opposite side (the upper side) of themetal tube 5 are available and the former is preferable. The temperatureat the time of melting is proper not to cause the cross-linking reactionand to give a proper viscosity for making the elastomer possible toenter the resin tube 4 and it is preferably 50 to 100° C.

After the elastomer is injected, a plug 7 is plugged. The plug 7 ispreferably made of a metal (e.g. a stainless steel). The plugging is forpreventing the elastomer from spilling by the time of completion ofmolding. In the case of the reaction type elastomer, cross-linkingreaction is preferably caused by heating. The heating method is carriedout by using an electric furnace or a drying apparatus in such a mannerthat the plug portion is kept in the lower side. The heating temperaturediffers depending on the heating mechanism and preferably 50 to 200° C.and more preferably 80 to 150° C. and heating is preferably carried outfor 1 to 12 hours. In this case, the temperature is required to beproper to avoid softening of the resin tube. The inner core in theportion of the resin tube is preferably pulled out after cooling to 50°C. or lower. In such a manner, a guide wire having the resin-moldedportion at the terminal

can be obtained.

Another invention is a guide wire comprising the tip end portion (a-2)made of a metal powder-mixed rubber.

The metal powder to be used is the same as the above-mentioned metalpowder having the high x-ray contrast property and preferably gold andplatinum. The form of the metal powder is not particularly limited andit is preferably in form of particles so as not to damage the bloodvessel even if the metal powder coming out of the surface of the rubberand spherical particles are more preferable. At the time of forming themetal powder-mixed rubber to be the tip (the most tip end) of the tipend portion (a-2), the rubber has to be smaller than the tip end part inorder to semi-circularly project the rubber out of the most tip end partand it is preferably 0.25 to 0.31 mm.

The material of the rubber may be the same as that of the elastomer andpreferably urethane elastomer and further preferably thermosettingurethane elastomer. The ratio of the elastomer forming the rubber andthe metal powder is preferably (10:90) to (90:10) by weight and morepreferably (15:85) to (50:50).

The form of the rubber is preferably semicircular. Because it is at thetip end part of the guide wire and therefore frequently brought intocontact with the blood vessel and thus scarcely causes physical damageson the blood vessel.

The production method may include mixing the metal powder with rubber,attaching a trace amount of the mixture to the tip end while keeping themixture from coming out the diameter and keeping the tip end of the tipend portion (a-2) in the lower side, and gradually lifting the tip endportion (a-2). The operation is preferably carried out by observing witha magnifying glass. Further, the mixture is cured in the curingconditions same as those in the case of using a hot air dryingapparatus. Further, at the time of integrally forming theabove-mentioned resin and the coil, the plug 7 is plugged after theinjection of the elastomer, a semi-circular recessed part may be usedfor plugging in place of the plug and after reaction by heating iscarried out, the plug is taken off to form the rubber mixture by onlyone time heating. In such a manner, a metal powder-mixed rubber with asemi-circular shape at the tip can be formed (the tip end part in FIG.2). The metal powder exists in the rubber and the rubber is same as theelastomer forming the tip endportion (a-2) of the guide wire and isextremely soft, hardly damages the blood vessel and safe as comparedwith a conventional wire with a silver solder at the most tip end. Bythe production method, a guide wire having the tip end having elasticityand composed of the high x-ray contrast unit (b) and the tip end portion(a-2) covered with the elastomer. In the case of the guide wire producedby such a production method, even if a doctor erroneously uses it andmakes it in habitual form, it can easily be amended. Further, a guidewire with an outer diameter as extremely thin as 0.25 to 0.31 mm can bemade available for practical use.

Next, a lubricating coating is formed on the entire or a part of thesurface of the foregoing obtained guide wire. Preferably the entiresurface is coated. The coating can be formed by treating the guide wirewith an anti-thrombus coating material which can firmly be stuck to thesubstrate, forms a highly durable coating and gives good anti-thrombusproperty and in-water lubricating property and slimy property. When theguide wire is inserted into the tissues and the coeloms of a human bodysuch as the blood vessel, the trachea, the urethra and the like, thereoccurs a problem that the thrombus adheres or the tissues stuck to theguide wire. Therefore, in order to avoid troubles in medical care at thetime of insertion, the guide wire is required to lessen the damages andscratches by the contact with the tissues and mucous membranes and forthat, it has been pointed out that a low friction material has to beused also for the guide wire. Therefore, it becomes effective to use theanti-thrombus coating material giving the above-mentioned functions.

In the invention, as the anti-thrombus coating material for forming thelubricating coating, conventionally used ones can be used. Practicalexamples are coating materials containing organic solvent and (1)polyvinyl ether-malefic anhydride copolymer, its partially esterifiedcopolymer, and/or silicone-containing fluoroacrylate polymer (JapanesePatent No. 2,696,053); (2) two or more copolymers selected fromN,N-dimethyl(meth)acrylamide, 2-hydroxyethyl (meth)acrylate, and2-(perfluoroalkyl) ethyl (meth)acrylate (Japanese Patent ApplicationLaid-Open No. 7-289630); (3)(2R,4R)-4-methyl-1-[N-((RS)-3-methyl-1,2,3,4-tetrahydro-8-quinolinesulfonyl)-L-alginyl]-2-piperidinedicarboxylicacid hydrate. In the invention, the lubricating coating is preferably ananti-thrombus coating containing polyvinyl ether-maleic anhydridecopolymer, its partially esterified copolymer, and/orsilicone-containing fluoroacrylate polymer. The production method of theanti-thrombus may be same as described in the above-mentioned document.Before the use of the above-mentioned anti-thrombus coating material,the above-mentioned primer maybe treated again. The treatment conditionsare preferably same as those described above. In the case of using theabove-mentioned anti-thrombus coating material, it is preferable toadjust the concentration and the viscosity by diluting the material withthe above-mentioned solvent. The concentration is preferably 0.1 to 20%by weight and more preferably 0.2 to 10% by weight. The viscosity ispreferably 1 to 200 mPa·s and more preferably 2 to 100 mPa·s. The driedcoating film thickness of the anti-thrombus coating material is 0.05 to30 pm, and more preferably 0.15 to 10 μm.

The obtained guide wire is subjected to immersion to the coatingmaterial up to a needed length, or spraying or brush applicationtreatment with the material at a normal temperature to 50° C., dried ata normal temperature for 10 hours or long to overnight, and heated at 50to 200° C., more preferably 80 to 150° C. for preferably 1 to 12 hours.

In the case of the anti-thrombus coating material of the above-mentioned(1), in order to provide the lubricating property, alkaline treatment iscarried out. The guide wire coated with the ant-thrombus coatingmaterial is further subjected to immersion treatment in a preferably0.01 to 1 N, more preferably 0.05 to 0.5 N alkaline solution of sodiumhydroxide, potassium hydroxide, sodium carbonate, sodium hydrogencarbonate, or aqueous ammonia, at 10 to 60° C. for preferably 10 to 60minutes, more preferably 20 to 40 minutes. After that, the guide wire iswell washed with purified water such as distilled water or ion-exchangedwater. In this case based on the necessity, it is effective to carry outwashing by an ultrasonic washing apparatus preferably for 5 minutes orlonger. After that the guide wire is dried at a normal temperature to50° C. for 1 to 10 hours. By this operation, the guide wire having thelubricating coating can be obtained.

The guide wire of the invention has a lubricating coating with heatresistance and wear resistance and durability in an optional lengthrange. Further, an extremely thin guide wire having an outer diameter asthin as 0.25 to 0.31 mm can be made available for practical use.

Hereinafter, the invention will be described along with Examples andComparative Examples, however it is not intended that the invention belimited to these illustrated embodiments. Hereinafter, the part(s)denotes the part(s) by weight.

PRODUCTION EXAMPLE 1

Sannix PP 1000 (polypropylene glycol with the number average molecularweight of 1,000; the ratio of terminal primary hydroxylation 3%;manufactured by Sanyo Chemical Industries, Ltd.) 87. 1 g and tris(pentafluorophenyl) borane 0.02 g were loaded into an autoclave with 200ml capacity, made of a stainless steel and equipped with a stirringapparatus and a thermostat apparatus and while the reaction temperaturebeing controlled at 60 to 70° C., propylene oxide 87.1 g was dropwiseadded for 12 hours and then aging was carried out at 65° C. for 3 hours.Next, after the reaction product was neutralized with an aqueous sodiumhydroxide solution, Kyowaad 600 (synthesized silicate, manufactured byKyowa Chemical Industry Co., Ltd.) 3.0 g and water were added at 70° C.for 1 hour. After the reaction product was taken out of the autoclave,it was filtered with a filter of 1 μm meshes and then dewatered toobtain a liquid-state polypropylene glycol (the number average molecularweight: 2,000) 156.8 g. The yield was 90%, the hydroxyl value was 55.9,and the ratio of the primary hydroxyl groups in the hydroxyl groups atthe terminals was 69%.

This liquid-state polypropylene glycol 23 g and propylene oxide adductof glycerin (the number average molecular weight: 5,000) 57 g wereloaded into a reaction chamber, dewatered at 120° C. in reduced pressureof 30 mmHg to lower the water content of the mixture to 0.03% or less.Next, the mixture was cooled to 80° C. and HD 19.1 g was added to thereaction chamber and reaction was carried out at 80±5° C. for 4 hours toobtain a urethane prepolymer having a terminal NCO content 2.2%.

The urethane prepolymer 100 g, the above-mentioned polypropylene glycol(the number average molecular weight:

2,000) 62 g, and a curing promoting catalyst (monobutyltin triacetate)0.01 g were kneaded by a planetary mixer for 30 minutes under reducedpressure to obtain two-component type elastomer resin raw material.

PRODUCTION EXAMPLE 2

The liquid-state polypropylene glycol of Production Example 1 (thenumber average molecular weight: 2,000) 40 g and propylene oxide adductof glycerin (the number average molecular weight: 5,000) 57 g wereloaded into a reaction chamber, dewatered in the same manner as thelatter half stage in the Production Example 1 at 120° C. in reducedpressure of 30 mmHg to lower the water content of the mixture to 0.03%or less. Next, the mixture was cooled to 80° C. and HDI 5.7 g was addedto the reaction chamber and reaction was carried out at 80±5° C. for 4hours to obtain a hydroxyl group-terminated urethane prepolymer(hydroxyl value: 4.2).

The urethane prepolymer 100 g and Cymel 303 (Mitsui-Saitec Corp: aminoresin) 2 g were kneaded by a planetary mixer for 30 minutes underreduced pressure to obtain thermosetting elastomer resin raw material.

PRODUCTION EXAMPLE 3

Glycol adipate polyester 183.8 g with a weight average molecular weight1,750 and neopentyl glycol 1.5 g were loaded into a reaction chamber,dewatered at 120° C. in reduced pressure of 30 mmHg in the same manneras the latter half stage in the Production Example 1 to lower the watercontent of the mixture to 0.03% or less. Next, the mixture was cooled to80° C. and HDI 18.5 g was added to the reaction chamber and reaction wascarried out at 80±5° C. for 4 hours to obtain a hydroxylgroup-terminated urethane prepolymer (hydroxyl value: 6.5).

The urethane prepolymer 100 g and Pestagon B-1530 (E-caprolactam blockedisocyanate, manufactured by Huls Corp.) 3 g were kneaded by a planetarymixer for 30 minutes under reduced pressure to obtain thermosettingelastomer resin raw material.

PRODUCTION EXAMPLE 4

Hydroxyl group-terminated urethane prepolymer 100 g obtained inProduction Example 3 and y-glycidoxypropyltrimethoxysilane 3 g werekneaded by a planetary mixer for 30 minutes under reduced pressure toobtain thermosetting elastomer resin raw material.

PRODUCTION EXAMPLE 5

Under stirring condition, toluene 100 parts was loaded into a flask andheated to 120° C. and a mixed solution containing methyl methacrylate 35parts, Fluowet MAE-812 [perfluoroalkylethyl (carbon atoms ofperfluoroalkyl part; 6 to 12) methacrylate; Clariant Japan] 55 parts,styrene 20 parts, 3-mercapatopropyltrimethoxysilane 7 parts,azobis(isobutyronitrile) 3 parts, and toluene 5 parts was dropwise addedfor 3 hours and reaction was carried out at the same temperature for 2hours. Further, azobis(isobutyronitrile) 0.3 part was added and reactionwas carried out at the same temperature for 3 hours. After cooling to aroom temperature, a silicone-containing f luoromethacrylate copolymercontaining solid matter 52.5% and having a weight average molecularweight 1,200 was obtained.

GANTREZ AN-139 (polyvinyl ether/maleic anhydride copolymer; the weightaverage molecular weight 41,000; manufactured by GAF Co.) 4 g was mixedwith methyl ethyl ketone 76 g and stirred and dissolved in therein.Next, the above obtained silicone-containing fluoromethacrylatecopolymer 20 g was gradually added and stirred and mixed at 100° C. for1 hour. After cooled to a room temperature, the obtained product wasdiluted with methanol/acetone (1/1; by volume) to obtain a coatingsolution with 5% solid matter.

EXAMPLE 1

As an inner core, a core wire with 0.25 mm outer diameter and 1, 800 mmfull length was tapered in the tip portion of 160 mm and the tip portionof 160 mm from the tip end was tapered to be narrow toward the tip andobtain an inner core with the outer diameter 0.04 mm at the most tipend. SUS 301-Ti, Ni alloy was used as the inner core material. Further aplatinum coil was inserted into the taper part. The core wire wasimmersed in a solvent mixture of isopropanol/ethanol (1/1: volume ratio)and washed at a normal temperature for 30 minutes. After dried by beingleft at a normal temperature for 2 hours, the obtained core wire wastreated with a primer.

As the primer, ADEKA BONTIGHTER HUx-350 (water-based urethane resin:manufactured by Asahi Denka Kogyo K. K.) diluted with water to adjustsolid matter to be 5% was used. While the base part 10 cm of the corewire was left as it was, the rest portion up to the tip end was coatedby immersion. After the core wire was pulled out and left still at anormal temperature for 12 hours, was set in an electric furnace andheated at 125° C. for 2 hours.

A silicone tube 200 mm with an inner diameter 0.25 mm and an outerdiameter 1.0 mm was made ready and about 20 mm taper coil part at thetip end of the core wire was inserted into the tube. Further, astainless pipe with an inner diameter 1.1 mm and an outer diameter 1.83mm was made ready and the silicone tube was pushed in around 20 mmlength of the inside of the silicone tube, that is up to the most tipend part. The tip end portion of 10 to 20 mm length between thestainless pipe and the silicone tube was sealed with a silicone plug(having a hole in the portion of the silicone tube).

“Monotan A-20” (reaction type urethane elastomer resin raw material:manufactured by Compounding Ingredients Ltd.) was set in a tank andmelted at 70 to 90° C. and the portion from tip end to the taperboundary (160 mm from the tip end of the core wire) coated with the tubewas immersed into the melted “Monotan A-20” to inject “Monotan A-20”from the lower part based on the capillary phenomenon. The resultingcore wire was pulled out and the silicone tube at the tip end portionwas plugged by a stainless plug.

Next, the core wire was set in an electric furnace while the plug partbeing in the lower side and thermosetting was carried out at 135° C. for7 hours. The core wire was taken out of the electric furnace and cooledto a room temperature and then the stainless pipe was taken off andsilicone tube was pulled out to obtain a guide wire A-1 having aspecified structure of the invention. The guide wire comprised the corewire having a length of the full body about 1,800 mm and an outerdiameter of 0.25 mm and a molded body of the urethane elastomercontaining the platinum coil in the tip end portion with a length of 160mm and an outer diameter of 0.25 mm. The tip end portion of the guidewire A-1 was found having the bending load about 4 g and the restorableload about 2 g. When the guide wire A-1 was x-ray-photographed, a highx-ray contrast image was obtained at the tip end part.

Further, the guide wire A-1 was hung while the tip end being kept in thelower side and a trace amount of a mixture of a gold powder (under 400meshes) 80 parts and “Monotan A-20” 20 parts at 70° C. was stuck to themost tip end and then the guide wire was slowly lifted up. The resultingguide wire was set in an electric furnace and heated at 135° C. for 7hours in nitrogen flow to cure the mixture and obtain a guide wire A′-1.As shown in FIG. 2, the tip end portion with a semi-circular shape wasfirmly attached. When the guide wire A′-1 was furtherx-ray-photographed, a high x-ray contrast image was obtained also at themost tip end part.

EXAMPLE 2

The core wire used in this Example was same as that of Example 1, exceptthat the outer diameter of the inner core was changed to be 0.31 mm from0.25 mm. Washing was carried out in the same manner as Example 1.

Primer treatment was carried out in the same manner as Example 1, exceptthat as a primer, “Silbond 49SF” (manufactured by Compounding IngredientLtd.) was used in place of “ADEKA BONTIGHTER HUX-350” used in Example 1.

The silicone tube used in this Example was same as that of Example 1,except that the outer diameter of the inner core was changed to be 0.31mm from 0.25 mm. The same stainless pipe as that of Example 1 was used.

The elastomer was molded in the same manner as that of Example 1, exceptthat the two-component type elastomer resin raw material produced inProduction Example 1 was used in place of “Monotan A-20”. Thereafter,same operation was carried out to obtain a guide wire B-1.

The guide wire B-1 comprised the core wire having a length of the fullbody about 1,800 mm and an outer diameter of 0.31 mm and a molded bodyof the urethane elastomer containing the platinum coil in the tip endportion with a length of 160 mm and an outer diameter of 0.31 mm. Thetip end portion of the guide wire B-1 was found having the bending loadabout 5 g and the restorable load about 3 g. When the guide wire B-1 wasx-ray-photographed, a high x-ray contrast image was obtained at the tipend part.

Further, with respect to the semi-circular-shape rubber at the most tipend part, the two-component type elastomer resin raw material producedin Production Example 1 was used in place of “Monotan A-20” but the restoperation was carried out in the same manner as Example 1 to obtainB′-1. When the guide wire B′-1 was x-ray-photographed, a high x-raycontrast image was obtained also at the most tip end part.

EXAMPLE 3

The core wire used in this Example was same as that of Example 1, exceptthat the outer diameter of the inner core was changed to be 0.31 mm.Washing was carried out in the same manner as Example 1.

Primer treatment was carried out in the same manner as Example 1, exceptthat as a primer, Polytail HE (polyolefin resin: manufactured byMitsubishi Chemical Corporation) was used in place of “ADEKA BONTIGHTERHUX-350” used in Example 1.

The silicone tube used in this Example was same as that of Example 1,except that the inner 0.25 mm diameter of the tube was changed to be0.31 mm. The same stainless pipe as that of Example 1 was used.

The elastomer was molded in the same manner as that of Example 1, exceptthat the thermosetting type elastomer resin, raw material produced inProduction Example 2 was used in place of “Monotan A-20”. Thereafter,same operation was carried out to obtain a guide wire C-1.

The guide wire C-1 comprised the core wire having a length of the fullbody about 1,800 mm and an outer diameter of 0.31 mm and a molded bodyof the urethane elastomer containing the platinum coil in the tip endportion with a length of 160 mm and an outer diameter of 0.31 mm. Thetip end portion of the guide wire B-1 was found having the bending loadabout 5 g and the restorable load about 3 g. When the guide wire C-1 wasx-ray-photographed, a high x-ray contrast image was obtained at the tipend part. Further, with respect to the semi-circular-shape rubber at themost tip end part, the thermosetting type elastomer resin raw materialproduced in Production Example 2 was used in place of “Monotan A-20” butthe rest operation was carried out in the same manner as Example 1 toobtain C′-1. When the guide wire C′-1 was x-ray-photographed, a highx-ray contrast image was obtained also at the most tip end part.

EXAMPLE 4

The elastomer was molded in the same manner as Example 1, except thatthe thermosetting type elastomer resin raw material produced inProduction Example 3 was used in place of “Monotan A-20”. Thereafter,same operation was carried out to obtain a guide wire D-1 and a guidewire D′-1. When the guide wire D′-1 was x-ray-photographed, a high x-raycontrast image was obtained also at the most tip end part.

EXAMPLE 5

The elastomer was molded in the same manner as Example 1, except thatthe thermosetting type elastomer resin raw material produced inProduction Example 4 was used in place of “Monotan A-20”. Thereafter,same operation was carried out to obtain a guide wire E-1 and a guidewire E′-1. When the guide wire E′-1 was x-ray-photographed, a high x-raycontrast image was obtained also at the most tip end part.

EXAMPLE 6

The guide wires A-1, B-1, C-1, D-1, and E-1 produced in Examples 1 to 5were immersed in the coating solution obtained in Production Example 5for 1 hour and after the coating solution was drained spontaneously, thewires were dried by air blow at a room temperature for 12 hours andheated at 100° C. for 7 hours in an electric furnace. After that, thewires were immersed in a 0.1N sodium hydroxide solution for 30 minutes,washed with flowing ion-exchanged water, dried at a room temperature for10 hours to obtain guide wires A-2, B-2, C-2, D-2, and E-2 each havinglubricating property. The guide wires were subjected to the followingtests.

(Anti-Thrombus Test)

The inguinal part of a domestic rabbit was opened and the femoral arterywas exposed and the anti-thrombus guide wires of the above-describedExample 6 were inserted into the artery of the abdominal region from theexposed part. In the same manner, the guide wire A-1 of Example 1 havingno coating of the above-mentioned coating material was inserted into theartery of the abdominal region of a domestic rabbit. On 36th day afterretention, heparin 200 units were injected to both domestic rabbits andthen slaughtered without bleeding blood. After the abdominal regionswere opened and the thrombus adhesion state to each guide wire wasobserved.

No thrombus was observed at all in the guide wires A-2, B-2, C-2, D-2,and E-2. On the other hand, thrombus 60 mg was observed adhering to theguide wire A-1. From these results, the guide wires A-2, B-2, C-2, D-2,and E-2 were made clear that they had the ant-thrombus property. Whenthe confirmation test was carried out by prolonging the retentionperiod, no thrombus adhesion to the guide wires A-2, B-2, C-2, D-2, andE-2 was observed even after 60-day retention.

(Underwater Lubricating Test)

The underwater lubricating properties were compared for the guide wireA-2 of Example 6 and the guide wire A-1 of Example 1. An apparatusillustrated in FIG. 3 was used for the comparison test. In FIG. 3, acylinder 14 having an outer diameter proper to be inserted into acylindrical container 13 was concentrically attached to the upper partin the inside of the cylindrical container 13 and the gap between thebottom part of the cylindrical container 13 and the cylinder 14 was keptto be 100 mm. A silicone sheet 15 with a thickness of 8 mm was attachedto the bottom part of the cylinder 14 and an aperture 16 with a diameterof 1.5 mm was opened in the center of the silicone sheet 15. A sample 17of the guide wire was inserted in the aperture 16 and pushed until thetip end was brought into contact with the bottom part of the cylindricalcontainer 13. The cylindrical container 13 and the cylinder 14 werefilled with purified water. The upper end of the sample 17 was bonded toa tensile tester and pulled at 500 mm/min cross-head speed and thefriction stress between the sample 17 and the silicone sheet 15underwater was measured.

The test was carried out for the guide wire A-2 and the guide wire A-1without coating, and the results are shown in FIG. 4. From the results,it was found that the guide wire A-2 of Example 6 had extremely lowfriction stress underwater and that it had uniform and excellentlubricating property in the full length.

(Slimy Test)

The guide wire A-2 of Example 6 and the guide wire A-1 of Example 1 weresubject to the slimy test. After the respective samples were immersed inice-water for 15 seconds and pulled out and the degree of the slimyfeeling, the slimy feeling retention time, and the unevenness of theslimy feeling were evaluated by hand feeling. The guide wire A-2 ofExample 6 showed high degree of the slimy touch and even repeatedfriction with hand in air for 5 minutes, the slimy touch did not lowerand no heat was left by hand. Further, in the entire length of the guidewire, uneven slimy feeling was observed. On the other hand, the guidewire A-1 did not have slimy feeling even immediately after the pullingand when the wire was rubbed with a hand in air, it was immediatelydried and shows high friction resistance and friction heat was felt bythe hand.

Industrial Applicability of the Invention The guide wire and itsproduction method of the invention have the following effects.

(1) A guide wire comprising an extremely thin inner core having an outerdiameter as narrow as 0.25 to 0.31 mm can be made available forpractical use.

(2) Since a gap is kept between the core wire and the coil in the mainpart portion at the tip end, the guide wire is easy to be bent, howeverthe bending habit can easily be amended since the production method ofthe invention employs the immersion method.

(3) The guide wire has a durable lubricating coating in an optionallength.

(4) Since the high x-ray contrast unit (the coil) and the resin areintegrated, no blood enters in the coil and no thrombus is formed.Further, at the time of taking the guide wire off, the coil is preventedfrom expansion or contraction and therefore the guide wire is highlysafe.

(5) The guide wire is soft and hardly damages the blood vessel since anelastomer is used for the metal powder-mixed rubber part at the most tipend.

Accordingly, the guide wire is not only useful as a conventional guidewire for insertion into the tissues and the coeloms of a human body suchas the blood vessel, the trachea, the urethra and the like, but also forthe blood vessel thinner than the blood vessels in the inside of thebrain and the kidney.

1. A guide wire comprising an inner core (a) composed of a main bodyportion (a-1) with a high rigidity and a tip end portion (a-2) smallerin diameter and lower in rigidity than the (a-1) and integrally formedtogether with the (a-1) and a high x-ray contrast unit (b) formed at thetip end portion (a-2), wherein the tip end portion (a-2) is resin-moldedwith the high x-ray contrast unit (b) contained therein;
 2. The guidewire according to claim 1, wherein the inner core (a) is treated with aprimer.
 3. The guide wire according to claim 1, wherein the resin usedfor the resin-molding is an urethane elastomer.
 4. The guide wireaccording to claim 3, wherein the urethane elastomer is thermally cured.5. The guide wire according to claim 1, wherein the tip end of the tipend portion (a-2) is made of a metal powder-mixed rubber.
 6. The guidewire according to claim 1, wherein the surface is entirely or partiallycoated with a lubricating coating.
 7. The guide wire according to claim6, wherein the lubricating coating is polyvinyl ether-malefic anhydridecopolymer, its partially esterified copolymer, and/orsilicone-containing fluoroacrylate polymer.
 8. A production method of aguide wire comprising an inner core (a) composed of a main body portion(a-1) with a high rigidity and a tip end portion (a-2) smaller indiameter and lower in rigidity than the (a-1) and integrally formedtogether with the (a-1) and a high x-ray contrast unit (b) formed at thetip end portion (a-2), by inserting a tip end portion (a-2) into a tubewith a larger outer diameter than that of the portion (a-2) andinjecting a resin raw material into the tube for resin-molding the tipend portion (a-2) containing the high x-ray contrast unit (b) and thendrawing out the tip end portion (a-2) from the tube.
 9. The productionmethod of the guide wire according to claim 8, wherein the inner core(a) is treated with a primer.
 10. The production method of the guidewire according to claim 8, wherein the resin used for the resin-moldingis an urethane elastomer.
 11. The production method of the guide wireaccording to claim 10, wherein the urethane elastomer is thermallycured.
 12. The production method of the guide wire according o claim 8,wherein the tip end of the tip end portion (a-2) is made of a metalpowder-mixed rubber.
 13. The production method of the guide wireaccording to claim 8, wherein the surface is entirely or partiallycoated with a lubricating coating.
 14. The production method of theguide wire according to claim 13, wherein the lubricating coating ispolyvinyl ether-maleic anhydride copolymer, its partially esterifiedcopolymer, and/or silicone-containing fluoroacrylate polymer.